1. Field of the Invention
This invention relates to a nail-driving device, and more particularly to a nail-driving device with a safety unit cooperating with a pusher for preventing the nail-driving device from firing when nails are exhausted from a magazine of the nail-driving device.
2. Description of the Related Art
Referring to FIG. 1, a conventional nail-driving device 1 includes a housing 11, a magazine 12, and a rigid safety rod 13. The housing 11 includes a handle 111, an air cylinder 112, a nail ejection seat 113, and a plunger 114. The plunger 114 is disposed movably on the handle 111. A trigger 116 is disposed pivotally on the housing 11. A trigger arm 115 is mounted pivotally on a free end portion of the trigger 116. The magazine 12 is connected to the nail ejection seat 113, and includes a row of nails (not shown), a pusher 121 for pushing the nails into the nail ejection seat 113 one at a time, and a projection 122 extending toward the nail ejection seat 113. The safety rod 13 is disposed movably in the housing 11, and has a workpiece-engaging end 131 projecting from the nail ejection seat 113, and a trigger-engaging end 132 opposite to the workpiece-engaging end 131. The trigger-engaging end 132 is movable into contact with a free end portion of the trigger arm 115. When the workpiece-engaging end 131 of the safety rod 13 is pressed against a workpiece (not shown), the safety rod 13 moves relative to the housing 11 so that the trigger-engaging end 132 comes into contact with the trigger arm 115. In this state, if the trigger 116 is actuated, the trigger arm 115 will push and move the plunger 114 for performing a nail-driving operation.
When the pusher 121 is moved to a position whereat the pusher 121 is adjacent to the nail ejection seat 113 due to the fact that no nails remain in the magazine 12, a portion of the safety rod 13 is impeded by the projection 122 from movement relative to the housing 11. Hence, the trigger-engaging end 132 cannot contact the trigger arm 115, thereby preventing the nail-driving device from firing.
The aforesaid conventional nail-driving device 1 suffers from a drawback. That is, in a state where the nails are exhausted from the magazine 12, when the workpiece-engaging end 131 of the safety rod 13 is pressed against the workpiece, the above-mentioned portion of the rigid safety rod 13 may strike on the projection 122. If this occurs, since the stroke force of the safety rod 13 against the projection 122 is not buffered, the safety rod 13, the pusher 121, and the workpiece may be damaged.